Thursday, July 7, 2011

PL 25/11: Good statistics advice

Filed under: IFLA, statistics — Tags: — plinius @ 10:51 am

Ray Lyons is a specialist in library statistics. A real professional. A genuine, honest-to-goodness specialist.

I transmit his good advice from a book by Niederman and Boyum.

Only Trust Numbers

  • If you want to be a good quantitative thinker, you must learn to make decisions on the basis of [evidence, which typically takes the form of] numerical information, even when that information conflicts with your instincts and perceptions…
  • Try to raise your level of trust in careful quantitative analysis, and reduce your confidence in hunches, theories, and casual observations.

Never Trust Numbers

Before we reconcile our apparently inconsistent advice, first let us explain why numbers are not worthy of your trust:

  • It’s because numbers can be wrong, are frequently misleading, and all too often have an agenda…
  • Even when accurate, numbers can easily mislead.
  • Quantitative data are seductive; they invite us to engage in the risky behavior of reading more into data than is warranted.

Treat Numbers as Answers

A number only gets to be useful when considered as the answer to a question. To be a good consumer of numbers, the reader must constantly ask himself:

  • To what question is the number (supposed to be) the answer?
  • Is it the correct answer to that question?
  • Is that the question to which I need an answer?’ ”


Every number I see is generated and presented by people who have an interest in how that number is used or interpreted.


Ray also says, in another blog post:

The principles of high quality graphical data presentation have been articulated by William Cleveland, Edward Tufte, Howard Wainer and others. Good graphing practice is based on these three rules:

  1. Be clear.  (Strive for clarity. – William Cleveland)
  2. Be fair and accurate.  (Tell the truth about the data. – Edward Tufte)
  3. Be thorough.  (‘You can see a lot just by looking.’ – Howard Wainer quoting Yogi Berra)

1 Comment »

  1. Dear Tord
    thank you its very usful, i will follow your advice

    Comment by Muhsen — Sunday, October 23, 2011 @ 1:27 pm

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